Improvement in vegetable parchment



Urrnn STATES PATENT OFFICE.

AMBROSE G. FELL, OF NEW YORK, N. Y., 'ASSIGNOR TO HIMSELF, WILLIAM H.PHELPS AND WILLIAM-H. SMITH, OF SAME PLACE.

IMPIROVEMEHNT IN VEGETABLE PARCHMENT.

Specification forming part of Letters Patent No. 170,360, dated November23, 1875; application filed March 31, 1875.

To all whom it may concern Be it known that I, AMBROSE G. FELL, of thecity, county, and State of New York, have invented a new and ImprovedVegetable Parchment, and that the following is a full,

. which is hereinafter described.

The material or substance com monly known as vegetable parchment, whilepossessing some of the qualities of parchment, is extremely brittle, andliable to fracture underordinary circumstances, so as to limit itsuseful application to a great extent. By my invention I produce aVegetable parchmen'tthatnot only possesses all the qualities of thesubstance heretofore known by that name, but it is rendered exceedinglytough and pliable, making it useful for every purpose to which parchmentand thin leather are now used.

My process consists in subjecting the paper, after it has been treatedby sulphuric or other acid or otherwise, to a compound solutionconsisting of glue, tungstate of soda, acetate of lead, and glycerine,in such proportions as will render the gelatine of the glue insolubleand tough by the action of the tnngstate of soda upon it, and at thesame time render the paper flexible by means of the glycerine. Thepermanency of this flexibility is due to the insoluble condition of thegelatine of the glue.

This solution retains the gelatine as long as the temperature is above180 Fahrenheit, but on cooling precipitates it in a leathery elasticcondition, which cannot be again dissolved on "again subjecting it tothe said temperature.

The above-described bath is applied to the vegetable parchment whileheated to said temperature of 180 Fahrenheit. The parchment being thustreated is next submitted to a solution of pyroxyline, the action ofwhich upon the parchment is as follows: The sudden reduction oftemperature precipitates the gelatine in the paper in the conditiondesired, while the mutual decomposition of the acetate Pb O s rbo so Thefirst solution above described may be of the following proportions, fromwhich I have obtained good results, viz: Water, one hundred gallons;glue, eighty pounds tungstate of soda, two and a half to four per cent.of the glue acetate of lead, ten per cent. of the glue; glycerine, threeto five per cent. of the glue.

These ingredients are thoroughly dissolved at 180 Fahrenheit or more,and the paper is immersed in the solution from two to three hours. It isthen removed, and the surplus liquid returned to the bath in anysuitable way. It is next immersed for a few minutes in a bath ofpyroxyline solution, highly dissolved, the bath consisting ofabout-Water, one hundred gallons, and pyroxyline solution, from ten tofifteen gallons. This solution in bath form is maintained at theordinary temperature, and the material, when taken from it, is wellworked in water, or a weak solution of sal-soda (carbonate of soda;)-but if plenty of water is used, and the paper is well washed, the use ofthe soda is unnecessary.

It is obvious that the exact proportions of the solutions above named,and the time of treatment, may be varied to some extent Withoutdeparting from the spirit of my inventionas, for instance, .I mightemploy compounds which, in their chemical action, might yield thedesired element, and thereby produce the same effect as though thatelement had been employed in its free condition.

After the material has been thus subjected to the chemical baths aboverecited, it may bedriedby passing it between heated calender-rolls,which will give it a smooth and desirable surface.

The product produced by the process substantially as above describedpossesses not onlythe well-known characteristics of natural skin orleather, but it is in many respects superior to it. It cannot be torn byany ordinary-manipulatioxiflt may be elastic or not,

' as desired; it is extremely pliable; waterproof and translucent;admits of dyeing in any desired color; hot water and boiling doesnotmaterially change its characteristics; exposure to the action offlame will not ignite it, but will cause it to shrivel and give out anodor like burning skin; its translucency is uniform throughout itssubstance, and not in blotches; its general appearance is likely todeceive persons who are experts in leather and skin, and they would beapt to pronounce it leather or skin upon examination; it is strongerthan leather, and, to a greaterdegree, indestructible. In fine, themicroscope or chemical analysis will alone determine that it is composedof a vegetable base gelatinized and collodionized.

Having thus described my inventiomwvhat I claim as new, and desire tosecure by Letters Patent, is-- 1. As a new article of manufacture,artilicial parchment, consisting of gelatinized and collodionized fiber,substantially as described.

2. The process hereinbefore described ifOI' treatingvegetableparchmentwith a solution of glue, tungstate of soda, acetate oflead, and glycerine, and with a solution of pyroxyline, in theproportions and in the manner substantially as and for the purposedescribed.

Witnesses:

H. L. WATTEN'BERG, G. W. PLYMPTON.

